1. Field of the Invention
The present invention relates generally to hand-operated tools, and especially tools that a user swings to make an impact upon a work-piece, whether the impact is for hitting, chipping, or cutting the work-piece. The present invention relates more especially to sledge hammers, axes, hatchets, picks, adzes, pulaskis, pick-axes, or other hitting, picking, chipping, or cutting tools that are moved, during use, in a direction including at least a component that is transverse to the longitudinal axis of the tool handle.
2. Background and Related Art
Traditional sledge hammers, picks, axes, and other impact tools that are swung, comprise an elongated handle and an impact, pick, chipping, or cutting head that is generally transverse to the longitudinal axis of the handle. These tools are used by swinging the tool toward the work-piece in an arc swing, wherein the swing moves through a plane that is generally perpendicular to the plane of the work-piece, or at least generally perpendicular to the plane of the desired impact. Frequently, the work piece is orientated so that the surface to be impacted is generally horizontal, and the swing plane is generally vertical. A vertical swing plane is common, for example, when a user is splitting wood for a woodpile or hammering a post into the ground. Alternatively, the work piece may be orientated so that the surface to be impacted is non-horizontal, and the swing plane is non-vertical. A non-vertical, possibly even horizontal, swing plane is common, for example, when a user is chopping down a tree or sledge-hammering a wall during building demolition.
For most swings of the tools of interest in this document, the swing action may be described as an arc swing wherein the user's shoulder(s) or elbow(s) act as a rotation point and the arm(s) swing the tool toward the work-piece in such a way that the tool head hits the work-piece, said swinging having at least a component of movement/force that is transverse to the longitudinal axis of the handle and is parallel to the axis of the tool head. In a vertical or generally vertical swing plane, the user usually prepares by lifting or swinging the tool generally over his/her shoulder to place the tool in a position of potential energy above the work-piece. The user typically grasps the handle of the tool with both hands, and raises the tool above his shoulder by various means, depending upon the tool, the user's strength and preference, and the obstructions around the user. The user may, for example, lift the tool up in front him/her and back generally over his/her shoulder in about a 180 degree arc before pausing and reversing the direction his/her arm movement to produce the forward, downward swing at the target. Alternatively, the user may lift the tool up beside or behind him/her to the position generally over his/her shoulder, prior to producing the forward, downward swing at the target. In a non-vertical swing, the user typically moves the tool rearward to a position behind him/her, and then, mainly using his/her own strength rather than gravity, swings the tool forward toward the target at whatever level and whatever angle is appropriate for reaching the target.
In any event, the user typically has his/her hands separated from each other during the preparatory part of the swing, that is, the lifting of the tool above the shoulder or the moving of the tool rearward to prepare for the forward swing. In the preparatory part of the swing, one hand typically is nearer the rear end (proximal end) of the handle and the other hand nearer the tool head (near the distal end of the handle). This hand separation helps the user more easily lift the typically-heavy tool head, before proceeding to deliver the forward swing and blow to the work-piece.
As the user swings the tool to deliver an impact, the user's rearward hand stays in place, or substantially in place, on the handle, and the forward hand typically slides proximally along the handle toward the rear end of the handle and, hence, toward the rear hand. This allows the tool to swing forward from the user to hit the work-piece without requiring the user to bend over very far. This also maximizes the force of the long-handled tool impacting the work-piece, as both hands are near the proximal end of the handle and increase leverage. This is the natural swing when using such tools, and it allows the user to use his/her strength to best advantage to produce a large impact of the tool against the work-piece.
Blaker (U.S. Pat. No. 271,303, issued Jan. 30, 1883) and Curry (U.S. Pat. No. 3,981,043, issued Sep. 21, 1976) disclose members that may be placed around conventional ax handles for gripping by the user's forward hand. Both of Blaker and Curry disclose flexible or compressible sleeve systems for reducing blistering of the hand or for shock absorption.
Blaker describes his device as a “slidable grip, formed of leather, vulcanized rubber, canvas, or other suitable materials, fitting the handle loosely, and of such size as to be readily and conveniently clasped in the hand, which grip is slipped on the handle before the lower grip is put on. This sliding grip will be found to be of the greatest usefulness in connection with the spring-handle, for a spring-handle is necessarily too small to be conveniently grasped or held in the hand, and if it were cased to secure a good hand-hold the casing would interfere with its elasticity, and the sliding grip is therefore a primary necessity in connection with a spring-hand, and moreover, it saves the hands from the blistering caused by the ordinary wooden handles until the hands get calloused or hardened.”
Curry describes his device as “a new and improved hand grip for the handle of a tool . . . to permit one hand of the user to either firmly grasp the handle of a tool or to slide along the handle of a tool wherein the tool handle requires grasping by both hands of the user . . . a new and improved hand grip adapted for sliding movement between stopping means disposed proximate both ends of a tool handle . . . Disposed between the stops is a hand grip sized to receive one hand of the user and so as to substantially circle the tool handle . . . The hand grip may be compressible in directions perpendicular to the length of the tool handle to permit non-sliding grasping of the handle when desired and may also be provided with end pieces compressible in directions parallel to the length of the tool handle to absorb shocks resulting from impact of the hand grip with the stops.”
Although Blaker and/or Curry may provide hand protection and/or cushioning, the inventor believes that these prior art devices do not address other inherent problems in the natural swing of the tools that is described above. In a typical swing, the user loosens his/her forward hand so that it can slide proximally along the handle toward the rear end of the handle, as described above. This loosening is problematic because it allows inaccuracy in the swing and the impact. Ideally, the handle and head both should be aligned in the swing plane as they approach and impact the work-piece, but, once the forward (distal) hand is loosened, the user has less control over the direction and orientation of the tool and especially over the direction and orientation of the tool head, and the tool frequently rotates 20-30 degrees and even up to 45 degrees or more, in the user's hands during the swing and before impact. This causes an inaccurate and/or inconsistent swing and impact. Because the user's forward hand is loosened and because the user's rearward hand is naturally flexible/compressible, the inventor believes that the tool frequently rotates to an extent that moves the tool head longitudinal axis TL out of the plane of the swing and changes the point and direction of impact on the target. Thus, “glancing blows” or off-center blows are often delivered or the target is completely missed.
The prior art devices of Blaker and Curry do not solve this problem because, the inventor believes, they provide a member that can move on the handle of the impact tool in more than just a longitudinal direction parallel to the length of the handle, and/or they provide a member that compresses, flexes, or shifts to allow the location of the central axis L of the handle relative to the hand to change during the swing. The inventor believes that a major problem in the “natural swing” and in devices such as Blaker and Curry is that they allow rotation of the slidable member that is provided on the handle and/or they allow the handle central axis L to shift relative to the slidable member, thus allowing rotation of the tool in the user's hand(s) and/or transverse shifting of the tool in the user's hands. The inventor believes, therefore, that there is a need for his invention that includes a slidable sleeve system with a system for preventing rotation or twisting and preventing transverse shifting, of the tool in the user's hand(s).